let a = ["a", "b", "c"];
// let a = { 0: "a", 1: "b", 2: "c" };

// for (let i = 0; i < a.length; i++) {
// 	console.log(i, a[i]);
// }

let b = "";
for (let i in a) {
	b += a[i];
	console.log(i, a[i], b);
}

for (let item of a) {
	console.log(item);
}

let c = {
	first: 0,
	second: 1,
	third: 3,
};
for (let key in c) {
	console.log(key, c[key]);
}
